1. Field of the Invention
The present invention particularly relates to a oneway clutch which is suitably used for an automatic transmission, etc., of a car.
2. Related Background Art
A oneway clutch for an automatic transmission of a car has seen increasingly widespread use in automatic transmission vehicles.
In the conventional oneway clutch device of this kind, cylindrical rollers each serving as a torque transmitting member and disposed radially between an inner member and an outer race member which is concentric with the inner member can take a torque transmitting position at which the inner member and the outer race member are united integrally and a non torque transmitting position at which the inner member and the outer race member may be rotatable relatively to each other. Such cylindrical rollers have been held by a retainer made of metal with biasing members. The retainer is fixed to the outer race member by two caulked side plates in the axial direction and through block bearings in a circumferential direction.
The metallic retainer in the conventional structure is formed of the first and second annular side members extended radially at both sides in the axial direction and pole portions connecting the first and second annular side members. In apertures defined by the first and second annular side members and the pole portions, the rollers and the biasing members for biasing the corresponding rollers to the torque transmitting positions are fitted or held, and also block bearings for positioning the retainer in the circumferential direction with respect to the outer race member are fitted or held, respectively. The positioning of the retainer in the circumferential direction with respect to the outer race member is effected by the first and second annular side members which sandwich the outer race member therebetween from the both sides thereof.
In this conventional oneway clutch, in order to retain the block bearings at the retainer, claws are integrally formed to protrude at a side plate of the retainer, and the claws are caulked into the other side plate, as disclosed, for example, in Japanese Utility Model Application No. 4-1403.
In such a conventional device, an accordion-formed leaf spring is used as the biasing member, and a plurality of these leaf springs are used to press the rollers to roller support parts of the pole portions to support the rollers.
However, when the inner race or the outer race member is rotated in a loose direction, i.e., in a non torque transmitting direction, a surplus drag torque acts on the torque transmitting members. As a result, there arises a problem that a so-called drag of the torque transmitting members is caused.